1. Field of the Invention
The invention relates to gas wells, and in particular, to a system and related components for automatically starting and stopping the pumping action of a well. More particularly, the invention relates to a well control system which starts the pumping action of a well when the pressures within the well casing and delivery tube reach a predetermined pressure differential, and which maintains this pumping condition for a predetermined and controlled time period.
2. Description of the Prior Art
Many gas wells do not operate continuously, but operate on an "on-off" pumping cycle based upon the availability of the fluids or gas flowing into the bottom of the well casing. This situation especially exists in low volume gas wells where the gas which is pumped from the well takes time to accumulate to suffient amounts and pressure for removal. It is most efficient to pump this gas from the well only when this predetermined amount has accumulated in the well, which in many wells does not occur on a regular timing cycle or basis.
Many of these low volume gas wells are operated by a preset timer which is adjusted according to the particular pumping or production experience for that well. The timer is set to turn the well on and to keep the well on a particular number of times throughout the day. The terms "pumping" or "well on" conditions means that a control valve in the well delivery pipe is open, which enables the gas pressure developed within the well to automatically pump or force the collected fluids at the bottom of the well up through the delivery tube and into the delivery pipe without requiring any electrical, mechanical or similar pumping means.
There are problems with such timer-controlled wells in that the volume of gas and its associated pressure may not have accumulated sufficiently for proper operation when the timer turns the well on. At other times the pumping or "on" cycle may be too long or too short for the volume of accumulated gas or other fluids causing the well to "drown out". Any of these situations may require the well to be shut down and "blown out", all of which takes an operator's time, and consequently, increases operating costs with lower production.
Other well control systems, in order to eliminate the problems incurred with preset timer controls, operate off the well pressure to start a predetermined timing cycle. This pressure may be measured directly from the well casing or delivery tube, or a combination thereof. In most of these types of control systems the well may be turned on and off by the casing pressure. Problems can occur with such systems in that the casing pressure may not drop low enough in certain situations to shut the well off, even though all of the fluid has been taken out of the well through the delivery tube. Also, many of these type systems use various components which are subject to continuous maintenance and upkeep.
Therefore, the need has existed for a pumping control system which actuates the well pumping on and off cycles in relationship to the pressure differential existing between the well casing and tubing, and in which a predetermined "well on" time period may be incorporated into the pumping cycle to insure that the well will remain on for only a predetermined, preset time period.